In a randomized 2 X 2 design, this 5-year study will test personal and environmental interventions to prevent smokeless and smoked tobacco use among Alaska Native and American Indian (Native American) youth in Alaska, Idaho, Montana, and Washington. Personal intervention, delivered to groups of Native youth, will cover ethnic pride and values, health, and self-image content and problem solving, coping, and communication skills. Environmental intervention, delivered to Native youths, families, and peers, will develop social and situational supports to prevent tobacco use. Subjects will be 3,584 Native American females and males, 11- to 13-years-old at time of initial involvement. Recruited from 28 sites, consenting subjects will be pretested and, by site, randomly divided into four conditions. Subjects in three conditions will receive either personal intervention or environmental intervention or both interventions; subjects in one condition will receive no intervention. All subjects will be posttested, then followed every 6 months. Semiannually, intervention condition subjects will receive pairs of booster sessions. To check within-condition reliability, process measures will be taken of both interventions. Outcome measures will quantify subjects' smokeless and smoked tobacco use and will assess variables associated with tobacco use. Saliva collections, subsequently assayed for thiocyanate and cotinine, will precede subjects' tobacco use reports. Community surveys with random subsets of households will occur at each collaborating site. Data analyses will describe the study sample, inferentially test condition differences, and partition influences on Native youths' tobacco use. The study is supported by Native tribal, reservation, and public schools in Alaska, Idaho, Montana, and Washington.